The present invention relates generally to woven fabric having metallic warp cords and non-metallic weft cords, and more specifically to woven wire fabric having weft cords comprised of a plurality of glass filaments encapsulated in a resorcinol-formaldehyde-latex adhesive.
Tire-reinforcement components are generally comprised of reinforcing elements, hereinafter referred to as warp cords, embedded in an elastomeric substance, such as natural or synthetic rubber. The use of metallic warp cords, comprised of metallic wires or cables, as reinforcing elements in tire reinforcement components, such as tread-reinforcing plies, is well known in the tire manufacturing technology. The warp cords may be embedded in the elastomeric substance by means of a calendering process. The calendering process for metallic warp cords may consist of arranging the desired number of metallic warp cords, that are pulled from a creel, into a predetermined orientation and then compressing an elastomeric substance around and between the adjacent warp cords to form a continuous sheet. This process is generally referred to in the tire manufacturing technology as "creel calendering". However, if the metallic warp cords have been interwoven with weft cords, the woven wire fabric is merely pulled from a roll of fabric that has been placed on a let-off device, through a calender which compresses an elastomeric substance around and between the adjacent warp cords and weft cords, and wound up onto a core on a take-up device. The sheet of " creel-calendered" or "woven wire" fabric is then cut to predetermined dimensions to form reinforcing components for tires or similar articles.
For purposes of describing and claiming the present invention, "warp cords" shall mean cords, wires, or cables, that are substantially parallel to, and equidistant from adjacent cords, wires, or cables, and that are intended to act as reinforcing elements when incorporated into a tire or similar article. In addition to warp cords, woven fabrics also have weft cords, sometimes referred to as "pick cords" or "fill cords". For purposes of describing and claiming the present invention, "weft cords" shall mean cords that are oriented substantially transverse to warp cords to hold the warp cords in a predetermined relationship to each other, parallel to and equidistant from adjacent warp cords, while not being intended to act as reinforcing elements in a tire or similar article. For purposes of describing and claiming the present invention, "woven wire fabric" shall mean a fabric comprised of metallic warp cords and non-metallic weft cords, formed by weaving. "Weaving" as used herein and in the appended claims means the interlacing of warp cords and weft filaments.
The use of woven wire fabric in the reinforcing components of tires is desirable because the spatial relationships of the warp cords of creel-calendered fabric are more susceptible to distortion during the manufacturing of a tire than those of woven wire fabric. However, the woven wire fabric that has been available up until now has not been without problems. The woven wire fabric that has been used in the past had weft cords of nylon or polyester which did not adhere as well as is desired to the elastomeric substance in which the woven wire fabric is embedded during the calendering process. The poor elastomer to weft cord adhesion in woven wire fabrics having nylon or polyester weft cords may result in the propagation of moisture along the cord and lead to widely spread corrosion of the metallic warp cords. The weft cords of a woven wire fabric made in accordance with the invention have very good adhesion characteristics with the type of elastomeric substances used in the manufacturing of tire-reinforcement components. A tire having tread-reinforcing plies of woven wire fabric according to the invention did not exhibit wide-spread corrosion of the metallic warp cords as a result of the propogation of moisture along the weft cords after a salt corrosion test. A salt corrosion test comprises making four cuts in the tread of a tire at its centerline, all the way down to the tread-reinforcing ply; then running the tire 3,000 kilometers. Every 10 kilometers the tire is run through a bath containing an aqueous NaCl salt solution. After the road use is completed the tread was removed from the tire, and the tread-reinforcing ply was inspected.
There is provided in accordance with one aspect of the invention a woven wire fabric comprising a plurality of metallic warp cords, each of said metallic warp cords being oriented substantially parallel to, and equidistant from, adjacent metallic warp cords; and a plurality of weft cords, said weft cords being interwoven with, and oriented substantially transverse to said metallic warp cords, each of said weft cords comprising a plurality of glass filaments encapsulated in a resorcinol-formaldehyde-latex adhesive.
There is provided in accordance with another aspect of the invention a tire having at least one tread-reinforcing ply comprising woven wire fabric which is comprised of: a plurality of metallic warp cords, each of said metallic warp cords being oriented substantially parallel to, and equidistant from, adjacent metallic warp cords; and a plurality of weft cords, said weft cords being interwoven with, and oriented substantially transverse to said metallic warp cords, each of said weft cords comprising a plurality of glass filaments encapsulated in a resorcinol-formaldehyde-latex adhesive.